Avalanche Rescue – Precognition and Training improve excavation times after complete avalanche burial – A randomized single blinded mannequin study

Introduction:

Death from asphyxia is the leading cause for mortality in totally buried avalanche victims. The chance of survival is 91% when extricated within 18 minutes but drops to 34% when burial time exceeds 35 minutes. Extrication and resuscitation measures must be initiated by companions, as survival chances are significantly higher. Until now no study has analysed different time points, where the victim's airway could be accessed or BLS-CPR was possible. The aim of the present study was to investigate the duration of separate time points during companion avalanche rescue and elucidate factors determining these time intervals.

Material and Methods:

This randomized, single-blinded mannequin study was performed with 18 medical students (13 male & 5 female). Participants had completed BLS or ALS courses and perform winter-sport activities regularly. Participants were randomized in gender, random order and number of rescuers. Resuscitation mannequins were buried in an artificial avalanche in three different positions. During extrication the times to extricate the mannequin, free its airways and to start CPR in the supine standard position, were evaluated. Rescue times were measured, and analysed with Students-T-Test, Fisher-exact-test and ONE-way-ANOVA.

Results:

Mean participants age was 23.1 ± 2.4 years. Median time to first contact was 2.51 minutes (0.60 – 8.58), to free airways 7.22 minutes (2.28 – 20.43) and to standard CPR position 10.06 minutes (2.97 – 24.93). Body position and single versus double rescuer scenario did not significantly influence extrication times (p = 0.362/p = 0.099). The sequence of test cycles was significant (p = 0.008). Double rescuers significantly improved extrication times in the second and third test cycles (p = 0.008). Participants with previous knowledge had much shorter extrication times than participants without (p = 0.015); mainly because they applied the correct shovelling technique (p = 0.018).

Conclusion:

This randomized, single-blinded mannequin study provides evidence that after complete avalanche burial the victim's airway can be uncovered within seven minutes but it take another three minutes to bring the victim into standard BLS-CPR position. Previous knowledge and training improved extrication times whereas the number of rescuers is not significant. Shorter extrication time in consecutive test cycle may be attributable to a learning effect and thus emphasises the importance of regular extrication training.